The present invention relates to a self-service terminal (SST). In particular, the invention relates to an SST having a plurality of interconnected modules. The invention also relates to a module for use in an SST and to a method of encrypting a communication for transmission between interconnected modules in a self-service terminal.
A conventional SST, such as an automated teller machine (ATM), comprises a plurality of modules that are interconnected by an internal network, such as an intranet or a proprietary network, for conveying data to each other.
In an ATM, typical modules include a card reader, a receipt printer, a cash dispenser, an encrypting keypad, and such like. Data conveyed from the keypad is encrypted to provide security against a third party monitoring communications on the network to obtain sensitive information such as a customer's personal identification number (PIN). Data conveyed to the printer and other modules is generally either not encrypted or encrypted using low security encryption techniques.
It is desirable to encrypt all communications between modules in an SST to minimize the possibility of information interception by a third party monitoring the communications.
Implementing industry standard cryptographic confidentiality for all communications between modules in an ATM would be expensive because of the additional hardware required to store an encryption key and to meet performance needs for the cryptographic operations. Industry standard cryptographic confidentiality would also introduce additional time delays in each transaction because each communication must be encrypted using a recognized algorithm before the communication is sent and then decrypted using an associated cryptographic key on receipt of the encrypted communication. This time delay introduced by computationally intensive encryption and decryption may be unacceptable to the owner and the customers of an ATM.